The invention relates to arrangements for urging a flat surface of a planar power semiconductive device against an underlying heat sink in good electrical and thermal contact therewith.
In known arrangements of this type, the semiconductive element, typically in the form of a round wafer or slice, is urged with a preferably pre-determined pressure against the heat sink by means of a biasing arrangement consisting of a stiff spring. In practice, it has been found that such spring severely limits the flexibility of the arrangement to adapt to wafers of differing materials and sizes, which correspondingly require different degrees of pressure for optimum thermal and electrical contact without the danger of breakage. In addition, the high localized force of the stiff spring against the wafer has been found to result in a progressively increasing unevenness of the force applied to the semiconductive element, thereby correspondingly decreasing the efficiency of the thermal and electrical contact.